I have a 472 Cadillac in my 49 Buick Super. Just installed a Vintage Air Compact gen 2 heater /air unit. I have one water connection on the passenger side just below the water neck, that routes the heater hose behind the alternator. Where do I connect the return hose? I thought it went to the back of the passenger side head, but that seems to be pressure also, so I get no flow through the heater. In the original 70 Fleetwood the return went to the radiator tank, not an option with my aluminum radiator. Any Ideas?
get a piece of steel tube that fits inside the lower radiator hose, and another piece the size that fits into the heater hose, poke a hole in the larger one, weld the smaller one to it....then cut the lower hose, and put your new part in line.
I installed my 472 in a daily driver car the 80s, so my answer may sound vague. Going by memory, a hose came from a cyl head fitting, and another joined with the upper radiator tank near a rad hose. I thought it was odd that both seemed to be unusual locations, but it did heat well, so there must have been a decent flow. On the donor Cad Fleetwood, one was cyl head and the other, I believe, was the upper rad tank. Actually, I think it had side-to-side horizontal radiator, so that actually translates to a heater hose fitting in the Radiator-Cap-Side tank. I'll have to look at my old hotrod to see where I connected mine for the transplant, but I'm pretty sure I duplicated it with an upper rad hose fitting to tap in. I tried to duplicate the Caddy method without a special radiator. It may sound odd that the upper rad tank was a tap in point, rather than the lower rad hose (suction line), BUT when you look at the system closely, the thermostat is also a dividing line between high pressure and low pressure sides of the system. It's not just the water pump that divides high/low. If one heater hose is on the block side of that restriction (cyl head high pressure), and the heater return line is on the other side of the thermostat, you still have a decent pressure differential to get the heater water flowing. I'll have to uncover the stored car to double check, but my memory seems to jive with your observations, and my heater did work well thru many winters. WHY BE ORDINARY ?
A connection on the water pump will be suction, including the lower radiator hose. Any connection on the upper radiator hose or the front of the block or intake will be pressure. You may be able to add a heater connection to the radiator tank next to the lower hose but that is just a WAG. I've never tried it an I don't know how efficient it would be.
I believe you are mostly correct, but not completely .... The lower rad hose would give you a strong suction, yes, but also don't forget that simply moving that heater suction-connection a little upstream, say to the upper part of thr radiator flow, but still on the exit side of the restrictive thermostat, you will still have a suction, being downriver from the restrictor, but you will then have a moderate pressure-drop suction rather than the strong pressure-drop suction from the lower hose. Make sense? I thought the Caddy method seemed odd too, until I saw that it worked well in my car, and traced it out a couple times and saw why. It was actually a choice between big pressure drop (lower hose), and moderate pressure drop (upper, but just after the thermostat), with Caddy engineers choosing the moderate pressure drop location to tap in to. WHY BE ORDINARY ?
Just an update I went with the Kats lower radiator heater connection. I tried to buy it from their website, but they wanted $14 to ship the $14 part. I found it at O' Riley's for $8 and picked it up 5 blocks from my house. Got it installed and works great. Thanks for all the help, Brian.
The Jalopy Journal
